The 'Block Island' meteorite reproduced in plastic at NASA’s Jet Propulsion Laboratory. Credit: NASA/JPL-Caltech
Captain Picard orders tea
“Tea, Earl Grey, hot.” Who doesn’t remember that famous command by Captain Picard’s of TV’s “Star Trek: The Next Generation”? While no one’s yet invented a replicator that can brew a cup of tea out of thin air, scientists have taken in step in that direction by creating an amazing replica of a Martian meteorite using a 3D printer.
Without the fuss and expense of a sample retrieving mission to Mars, NASA scientists now have a realistic, true to life facsimile of the ‘Block Island’ meteorite discovered by the Opportunity Rover in 2009. Block Island, an iron-nickel meteorite similar to those found at Meteor Crater in Arizona, is the largest meteorite found on the Red Planet.
The real Block Island, the largest meteorite yet found on Mars, photographed by Opportunity’s panoramic camera.Credit: NASA/JPL-Caltech/Cornell
Measuring about two feet (60 cm) across, it’s about the size of picnic cooler and weighs an estimated 1,000 pounds. The replica’s made of plastic – you could tote it around like a … picnic cooler.
Analysis of Block Island’s composition using the rover’s alpha particle X-ray spectrometer confirmed that it’s rich in iron and nickel. Scientists based the design of the plastic meteorite on detailed measurements and stereo images taken by Opportunity’s panoramic camera.
Get out your red-blue plastic glasses to get a look at Block Island in stereo. Credit: NASA/JPL-Caltech
The rover made a 360-degree study of the meteorite five years ago taking measurements and many stereo images. But because Opportunity couldn’t see every square inch of the rock, the missing data created holes in the computer model, making it a poor candidate for 3D printing.
Last summer, scientists got around that problem by filling in the missing data and building small scale models of Block Island. To build the life-sized rock, they created depth meshes of the meteorite’s surface from six positions, then combined them into a three-dimensional digital model, according to researcher Kris Capraro of NASA’s Jet Propulsion Laboratory.
Researcher Kris Capraro (second from left) adds the finishing touches of realistic color to a model of the “Block Island” meteorite.Credit: NASA/JPL-Caltech
The printer built the meteorite from ABS plastic, the same material used in Lego bricks, with cord the width of the plastic line in your weed-whacker. One small problem remained before the replica could be executed – it was too big to fit in the printer’s building space. So researchers broke up the computer model of the meteorite into 11 sections. Printing took 305 hours and 36 minutes.
Researchers created each of 11 pieces in the 3D printer and glued them together to build the true-size model. Credit: NASA/JPL-Caltech
The sections were assembled and then painted to match the real rock. Said Capraro: “it’s the next best thing to bringing back real Martian rock samples back to Earth.”
Scientists hope someday to use 3D printing to not only replicate more Mars rocks but terrains across the solar system.
This map shows the paths of Ceres and Vesta in Virgo through late June at five-day intervals. Vesta is currently magnitude +5.8 and Ceres 7.0. Both are easily visible in binoculars from suburban and rural skies. A wide view map below will help you navigate from nearby bright Mars to Zeta Virginis. From Zeta, star hop to either asteroid. Stars are shown to about magnitude +8.5. Click to enlarge. Created with Chris Marriott's SkyMap software
Don’t let them pass you by. Right now and continuing through July, the biggest and brightest asteroids will be running on nearly parallel tracks in the constellation Virgo and so close together they’ll easily fit in the same binocular field of view. The twofer features Ceres (biggest) and Vesta (brightest) which are also the prime targets of NASA’s Dawn Mission. Now en route to a Ceres rendezvous next February, Dawn orbited Vesta from July 2011 to September 2012 and sent back spectacular photos of two vast impact basins, craters stained black by carbon-rich asteroids and parallel troughs that stretch around the 330-mile-wide world like rubber bands.
This mosaic of Vesta synthesizes some of the best views the spacecraft had of the giant asteroid. The towering mountain at the south pole – more than twice the height of Mount Everest – is visible at the bottom of the image. The set of three craters known as the “snowman” can be seen at the top left. Credit: NASA/JPL-Caltech/UCAL/MPS/DLR/IDA
Astronomers used Dawn’s gravity data to discover Vesta is more like a planet than anyone had supposed. Deep beneath its crust, composed of lighter minerals, lies a denser iron core. Most asteroids were too small to generate enough interior heat through the decay of radioactive elements to melt and “differentiate” into core, mantle and crust like the terrestrial planets. Thanks to our new understanding, you’ll hear Vesta referred to as a ‘baby planet’.
A full 5.3 hour rotation of Vesta using photos taken by Dawn. Credit: NASA
Studies of its crustal rocks showed a match to a clan of basaltic meteorites called howardites, eucrites and diogenites. Many of these formerly volcanic rocks that trace their origin to Vesta are found in numerous private and institutional collections. With a little homework, you can even buy a slice of Vesta on eBay, making for one of the least expensive sample return missions ever undertaken.
Dawn’s Greatest Hits at Vesta – A quick summary of key discoveries accompanied by electric guitar
While Vesta is a rocky body, Ceres shows telltale signs of water and iron-rich clay. Like Vesta, it also appears to have cooked itself into denser core and lighter crust. Because Ceres is less dense than Earth, astronomers believe water ice may be buried beneath its dusty crust.
Dwarf planet Ceres (right) is located in the asteroid belt, between the orbits of Mars and Jupiter. Observations by ESA’s Herschel space observatory between 2011 and 2013 found that the dwarf planet has a thin water-vapor atmosphere. It’s the first unambiguous detection of water vapor around an object in the asteroid belt. Credit: ESA/ATG medialab
Earlier this year, astronomers working with the Herschel Space Telescope announced the discovery of plumes of water vapor blasting from two regions on the dwarf planet’s surface. While Ceres is an asteroid it’s also a member of a select group of dwarf planets, bodies large enough to have crunched themselves into spheres through their own gravity but not big enough to clear the region they orbit of smaller asteroids.
Vesta (left) and Ceres. Vesta was photographed up close by Dawn, while the best views we have to date of Ceres come from the Hubble Space Telescope. Notice the bright white spot which is still a mystery. Credit: NASA/ESA
Ceres and Vesta will be gradually drawing closer in the coming weeks and months until on July 5 only 10 arc minutes (one-third the diameter of a full moon) will separate them. They’ll also be fading, but not so much that binoculars won’t show them throughout this excellent dual apparition. Vesta will only dim to magnitude +7 by July 1, Ceres to 8.4. Come mid-June I’ll return with a detailed map showing how best to see the dynamic duo during their close conjunction.
To find your way to the 4th magnitude stars Zeta and Tau Virginis, which you can use with the detailed map to guide you to Ceres and Vesta, start with brilliant Mars in the southern sky and look about one fist to the left or east to spot Zeta. Map shows the sky around 10 o’clock local time in late April. Stellarium
Sure, both Ceres and Vesta look exactly like stars even in large amateur telescopes, but sampling photons from real asteroids while listening to the sound of frogs on a spring night is my idea of a good time. Maybe yours too. Good luck!
A multiple frame picture of the rock falling, taken from a video taken during a skydive in 2012. Credit and copyright: Anders Helstrup, used by permission.
For all those involved with the initial investigation of the skydiver and the possible meteorite, they now feel they have resolution to their puzzle, thanks to the beauty of crowdsourcing. The rock that showed up in a video taken during a skydive in Norway in 2012 was likely just a rock — accidentally packed in the parachute — and not a meteoroid.
Steinar Midtskogen, from the Norwegian Meteor Network who was involved in the initial investigation of the video, suggested an adaptation of Linus’s Law to explain what has happened in the past week: “Given enough eyeballs, all mysteries are shallow.”
With all the comments, opinions and analysis following the release of the video last week, the team of scientists and video experts from Norway have conceded that the likelihood of the rock being a meteoroid is extremely low. After nearly two years of analyzing the video, the Norwegian team was unable to fully resolve the puzzle, and so they went public, hoping to get input from others.
“We were left with scenarios that we were unable to find possible solutions for against something that fits but is extremely improbable, though possible,” Midtskogen wrote on the NMN website. “We seemed to get no further, and we decided to go public with what we had and at the same time invite anyone to have a go at the puzzle. … We expressed our hope that it would go viral and scrutinized for something that we might have missed, and the result was beyond our expectations.”
The group welcomed all the input (and criticism) but were especially swayed by the ballistics analysis provided by NASA planetary scientist Dr. Phil Metzger, who posted his investigation on Facebook:
Here is my conclusion: the ballistics are consistent with it being a small piece of gravel that came out of his parachute pack and flew past at close distance. The ballistics are also consistent with it being a large meteorite that flew past at about 12 to 18 meters distance. It could be either one, but IMO not anything in between. Based on the odds of parachute packing debris (common) versus meteorite personal flybys (extremely rare), and based on the timing (right after he opened his parachute), I vote for the parachute debris as the more likely.
His three plots are below:
Ballistics analysis from Dr. Phil Metzger: The first one shows how the measured and predicted velocity agree only at the two different distances mentioned above. The second assumes it was parachute debris, and shows the velocity of the debris as a function of time after being released from his pack. the third shows the separation between the skydiver and the debris as a function of time. Note that the debris passes the skydiver at 12 seconds after the debris was released, which is the same amount of time in the video from when the drogue chute was opened until the debris passed the skydiver.
Metzger concluded the likely outcome is that a small piece of gravel about 3.3 cm in diameter flew by the camera by at about 30 meters per second, or 10 meters per second relative to the skydiver.
But while Metzter feels Occam’s razor favors parachute debris, he said his model only shows feasibility.
“I don’t consider it to be a smoking gun,” he told Universe Today. “There could be other, better scenarios.”
And so, Midtskogen told Universe Today, while the rock being a meteoroid isn’t completely ruled out, they feel the best answer is that it was a small rock embedded in the chute, and no further analysis is needed.
“I can confirm that the group will no longer do coordinated work on this,” Midtskogen said via email. “I think all of us feel confident about the conclusion and won’t work more on this individually either – although here I can only speak for myself. It was shown how a pebble packed in the chute could reappear well above the chute, and there is no strong evidence against a small size, so this has been easy to accept.”
While this rock ended up not likely to be a meteoroid, Midtskogen added, the crowdsourcing and interest in the video was overwhelming and encouraging.
“So, no meteorite, but a good story,” he said good-naturedly in his email to Universe Today. “Our mood is still good, and we talk about putting up a plaque at ground zero: “On 17th June 2012 a pebble fell here, witnessed by 6 million people on YouTube”.
Additionally, the skydiver, Anders Helstrup, seemed relieved more than anything.
“After all we seem to have found a more natural explanation to the video,” he told Universe Today. “And that is a good thing. I see that this had to have been MY mistake – packing a pebble into my parachute (I always pack myself). Our intention was to find out more and this way let the story out in the public, for people to make up their own minds. This became way bigger than I had imagined.”
In the end, while this story was not as fantastic as it might have been, it shows the beauty of crowdsourcing and using science to analyze a puzzle. And I readily admit to being overly enthusiastic in my initial article about this being a meteoroid, but I have to agree with Phil Plait who may have said it best in his update today: I would have loved to have this to have been a real meteoroid, but I’m glad this worked the way it did:
The video-makers were honest, did their level best to figure this out, and when they got as far as they could, they put it out to the public. And when it was shown to not be what they had hoped, they admitted it openly and clearly.
— Phil Plait
A multiple frame picture of the rock falling, taken from a video taken during a skydive in 2012. Credit and copyright: Anders Helstrup, used by permission.
It sounds like a remarkable story, almost unbelievable: Anders Helstrup went skydiving nearly two years ago in Hedmark, Norway and while he didn’t realize it at the time, when he reviewed the footage taken by two cameras fixed to his helmet during the dive, he saw a rock plummet past him. He took it to experts and they realized he had captured a meteorite falling during its “dark flight” — when it has been slowed by atmospheric braking, and has cooled and is no longer luminous.
Respected Norwegian astrophysicist Pål Brekke confirmed to Universe Today that the story is true and the video is authentic. “I was part of the investigation – and kept secret for two years – in hope of finding the meteorite,” Brekke said via a conversation on Twitter.
Since the search for the meteorite has come up empty so far, Helstrup’s story and video has been released in an effort to recruit more people to look for the rock — and to confirm that this actually was a meteorite.
“It has been a little hard to keep it as a secret,” Helstrup told Universe Today via email, “but everyone has been loyal to the project and helped us out!”
Here’s the video:
The rock zooms by at about :15 in this video:
You can watch a slower version in the video below.
Helstrup has been searching with friends, family and volunteers after getting advice from experts from the Geological Museum in Oslo, Norwegian Space Centre and Norwegian meteor network, making painstaking efforts to pinpoint the location of where the meteorite fell.
“The meteorite has for sure some possible hiding spots,” Helstrup said. “There is a forest with lots of different places it can easily disappear. Even if there is several areas where it would be found easily, there is a river, some marshy spots and areas and lots of high grass. Therefore the best chance of a finding would be in springtime. But we have high hopes!”
Finding the rock would provide the definitive confirmation it really was a space rock that Helstrup captured on film. There’s been much debate about the veracity of both the video and the claim (read Phil Plait’s look at the evidence) but in fact, it is Helstrup who might be most skeptical this was a meteor. There are experts, however, who say there is no doubt.
“It can’t be anything else,” said geologist Hans Amundsen, quoted in the Norwegian publication NRK. “The shape is typical of meteorites – a fresh fracture surface on one side, while the other side is rounded.”
He added that the meteorite may have been part of a larger rock that had exploded perhaps 20 kilometers above Helstrup.
What if the rock would have hit Helstrup or his diving partner? Amundson said the rock would have cut him in half.
“Imagine a 5 kilo rock hitting you in the chest at 300 kilometers per hour,” Amundson says in the video. “That would have led to quite an accident investigation.”
This is unique because — if confirmed — this is the first time a meteor in dark flight has been captured on film.
“Fireballs entering the atmosphere have been filmed many times,” says Morten Bilet in the video. Bilet is a meteorite expert. “This is unique because it was filmed during its so called “dark flight” – after it has been burned out. That’s never been done before so this is something new and exciting.”
We’ve asked Helstrup to keep us posted on any developments in this story or if the meteorite is found.
A scanning electron microscope image of a small section of a meteorite found evidence of past water in a Martian meteorite (specifically, in the form of tunnels and microtunnels). The meteorite is called
Yamato 000593. The rock was originally recovered in Antarctica in 2000 and is believed to have come from Mars. Credit: NASA
Could this meteorite show evidence of ancient water and life on Mars? That’s one possibility raised in a new paper led by NASA and including members of a team who made a contentious claim about Martian microfossils in another meteorite 18 years ago.
“This is no smoking gun,” stated lead author Lauren White, who is based at NASA’s Jet Propulsion Laboratory, of the findings released this week. “We can never eliminate the possibility of contamination in any meteorite. But these features are nonetheless interesting and show that further studies of these meteorites should continue.”
The new, peer-reviewed work focuses on tunnels and microtunnels the scientists said they found in a meteorite called Yamato 00593. The meteorite is about 30 pounds (13.7 kilograms) and was discovered in Antarctica in 2000. The structures were found deep within the rock, NASA stated, and “suggest biological processes might have been at work on Mars hundreds of millions of years ago.”
Scientists believe the 1.3-billion-year-old rock left Mars about 12 million years ago after an impact threw it off the surface. It reached Antarctica 50,000 years ago and after it was found in 2000, was analyzed and believed to be a “nakhlite”, or a kind of Martian meteorite. “Martian meteoritic material is distinguished from other meteorites and materials from Earth and the moon by the composition of the oxygen atoms within the silicate minerals and trapped Martian atmospheric gases,” NASA stated.
An asteroid impacts ancient Mars and send rocks hurtling to space – some reach Earth
There are two things in the meteorite that caught the attention of scientists. One is the aforementioned tunnels and microtunnels, which they say are similar to those altered by bacteria in basalt on Earth. The second is tiny, carbon-enriched spherules (in the nanometer to micrometer range) between layers in the rock — structures similar to another Martian meteorite (Nakhla) that struck Egypt in 1911. In that case, the rock was recovered quickly after landing and still had the same spherules, the researchers noted.
The authors said it’s possible that these structures could be explained by other mechanisms besides life, but said the similarities to what they have found on Earth “imply the intriguing possibility that the Martian features were formed by biotic activity.”
The research team includes NASA’s David McKay (who died a year ago), Everett Gibson and Kathie Thomas-Keptra. In 1996, these same scientists (then led by McKay) found “biogenic evidence” in a meteorite called Allen Hills 84001, but other science teams have disagreed with the findings. There have been a lot of papers about this particular meteorite, and you can read more about the controversy in this 2011 Universe Today article.
Chelyabinsk fireball recorded by a dashcam from Kamensk-Uralsky north of Chelyabinsk where it was still dawn. A study of the area near this meteor air burst revealed similar signatures to the Tall el_Hammam site.
Looking at the power of the Chelyabinsk meteor (which struck a year ago and is visible starting around 1:15 in the video above) is still terrifying all these months later. Happily for those of on Earth worried about these big space rocks, the world’s space agencies are taking the threat seriously and are starting to implement new tracking systems to look out for more threatening space rocks.
“It was a pretty nasty event. Luckily, no one was killed but it just shows the sort of force that these things have,” said Alan Harris, senior scientist of the DLR Institute of Planetary Research in Berlin, in this new European Space Agency video.
An asteroid that is only about 100 meters (328 feet) in diameter, for example, “could actually completely destroy an urban area in the worst case. So those are the things we’re really looking out for and trying to find ways to tackle.”
Check out the video for some examples of how the Europeans are talking about dealing with this problem, including a fun comparison to cosmic billiards and a more serious discussion on how to shove these rocks aside if they were on a collision course with our planet.
Chelyabinsk fireball recorded by a dashcam from Kamensk-Uralsky north of Chelyabinsk where it was still dawn. A study of the area near this meteor air burst revealed similar signatures to the Tall el_Hammam site.
Wonder and terror. Every time I watch the dashcam videos of the Chelyabinsk fireball it sends chills down my spine. One year ago today, February 15, 2013, the good citizens of Chelyabinsk, Russia and surrounding towns collectively experienced these two powerful emotions as they witnessed the largest meteorite fall in over 100 years.
Incredible compilation of dashcam and security camera videos of the fireball
The Chelyabinsk fall, the largest witnessed meteorite fall since the Tunguska event in 1908, exploded with 20-30 times the force of the atomic bomb over Hiroshima at an altitude of just 14.5 miles (23 km). Before it detonated into thousands of mostly gravel-sized meteorites and dust, it’s estimate the incoming meteoroid was some 66 feet (20-meters) end to end, as tall as a five-story building. The shock wave from the explosion shattered windows up and down the city, injuring nearly 1,500 people.
Atmospheric friction pressure on the Chelyabinsk meteoroid caused it to explode to pieces and send a shock wave across the land below. Pictured is a selection of typical small, fusion-crust covered Chelyabinsk meteorites recovered shortly after the fall. The U.S. penny is 9mm in diameter. Credit: Bob King
For nearby observers it briefly appeared brighter than the sun. NASA Meteorite researcher Peter Jenniskens conducted an Internet survey of eyewitnesses and found that eye pain and temporary blindness were the most common complaints from those who looked directly at the fireball. 20 people also reported sunburns including one person burned so badly that his skin peeled:
Map showing the trajectory of the main fireball in yellow (and two additional explosions at top left). The pink oval, called the strewnfield, is where the densest concentration of meteorites were found. Click to see additional maps. Credit: Svend Buhl and K. Wimmer
“We calculated how much UV light came down and we think it’s possible,” Jenniskens said. Perhaps surprisingly, most of the meteoroid’s mass – an estimated 76% – burned up and was converted to dust during atmospheric entry. It’s estimated that only 0.05% of the original meteoroid or 9,000 to 13,000 pounds of meteorites fell to the ground.
No video I’ve seen better captures the both the explosion of the fireball and ensuring confusion and chaos better than this one.
The largest fragment, weighing 1,442 lbs. (654 kg), punched a hole in the ice of Lake Chebarkul. Divers raised it from the bottom muck on Oct. 16 last year and rafted it ashore, where scientists and excited onlookers watched as the massive space rock was hoisted onto a scale and promptly broke into three pieces. Moments later the scale itself broke from the weight.
The 26-foot-wide (8-meter) hole punched in the ice of Chebarkul Lake by the largest fragment of the Chelyabinsk meteorite. Credit: Eduard Kalinin
There were plenty of meteorite to go around as local residents tracked down thousands of fragments by looking for holes pierced in the snow cover by the hail of space rocks. Working with hands and trowels, they dug out mostly small, rounded rocks covered in fresh black fusion crust, a 1-2 mm thick layer of rock blackened and melted rock from frictional heating by the atmosphere. According to the Meteoritical Bulletin Database entry, the total mass of the recovered meteorites to date comes to 1,000 kg (2,204 lbs.) with locals finding up to more than half of that total.
Animation of the orbit Chelyabinsk meteoroid via Ferrin and Zuluaga. Meteoroid is the name given a meteor while still orbiting the sun before it enters Earth’s atmosphere.
Thanks to the unprecedented number of observations of the fireball recorded by dashcams, security cameras and eyewitness accounts, astronomers were able to determine an orbit for Although some uncertainties remain, the object is (was) a member of the Apollo family of asteroids, named for 1862 Apollo, discovered in 1932. Apollos cross Earth’s orbit on a routine basis when they’re nearest the sun. Chelyabink’s most recent crossing was of course its last.
Chelyabinsk meteorites tell the tale of an earlier impact with another asteroid 4.452 billion years ago. Many specimens are pale white with small chondrules typical of LL5 chondrites. A closer look shows fine, dark shock veins of melted glass. Other fragments are made of pure impact melt, rock shocked-heated, melted and blackened by impact. Credit: Bob King
Chelyabinsk belongs to a class of meteorites called ordinary chondrites, a broad category that includes most stony meteorite types. The chondrites formed from dust and metals whirling about the newborn sun some 4.5 billion years ago; they later served as the building blocks for the planets, asteroids and comets that populate our solar system. Chondrites are further subdivided into many categories. Chelyabinsk belongs to the scarce LL5 class — a low iron, low metal stony meteorite composed of silicate materials like olivine and plagioclase along with small amounts of iron-nickel metal.
Most of the Chelyabinsk meteorites were shattered and broken during the explosion / shock blast, revealing brecciation, metal and shock veins in their interiors. Credit: Bob KingA thin slice of Chelyabinsk impact melt breccia. Flows of once-molten rock (paler gray) surround islands of less altered material. A small iron nickel nodule is seen at lower left. Credit: Bob King
A closer look at Chelyabinsk meteorites reveals a fascinating story of ancient impact. Remarkably, the seeds of the meteoroid’s atmospheric destruction were sown 115 million years after the solar system’s formation when ur-Chelyabinsk was struck by another asteroid, suffering a powerful shock event that heated, fragmented and partially melted its interior. Look inside a specimen and the signs are everywhere – flows of melted rock, spider webby shock veins of melted silicates and peculiar, shiny cleavages called “slickensides” where meteorites broke along pre-existing fracture planes.
Slickensides on a Chelyabinsk meteorite fragment where the fragment broke along a pre-existing fracture plane. Credit: Bob King
Jenniskens calculated that the object may have come from the Flora family of S-type or stony asteroids in the belt between Mars and Jupiter. Somehow Chelyabinsk held together after the impact until nearly the time it met its fate with Earth’s atmosphere. Researchers at University of Tokyo and Waseda University in Japan discovered that the meteorite had only been exposed to cosmic rays for an unusually brief time for a Flora member – just 1.2 million years. Typical exposures are much longer and indicate that the Chelyabinsk parent asteroid only recently broke apart. Jenniskens speculates it was likely part of a loosely-bound, rubble pile asteroid that may have broken apart during a previous close encounter with Earth in the last 1.2 million years. The rest of the rubble pile might still be orbiting relatively nearby as part of the larger population of near-Earth asteroids.
Rivulets of melted rock line the fusion crust of melted rock on this small Chelyabinsk meteorite. Credit: Bob King
Good thing Chelyabinsk arrived pre-fractured. Had it been solid through and through, more of the original asteroid might have survived its fiery descent and wreaked even more havoc in in its wake.
We’re fortunate that Chelyabinsk contains a fantastic diversity of features and that we have so many pieces for study. Surveys have found some 500 near-Earth asteroids. No doubt some are part of the parent body of Chelyabinsk and may grace our skies on some future date. Whatever happens, Feb. 15, 2013 will go down as a very loud “wake-up call” for our species to implement more asteroid-hunting programs both in space and on the ground. Enjoy a few more photos of this incredible gift from space:
This Chelyabinsk “nosecone” or “bullet” weighs just 0.35g. It displays a beautiful streamlined form from its flight through the atmosphere. Credit: Bob KingCheck out the bubble texture on this one. Heated by friction with the air, this fragment shows bubbly crust from escaping gases. Credit: Bob KingSlice of Chelyabinsk showing mildy shocked areas (light brown) cut by thick dark veins of shock-darkened material. Credit: Bob KingSome Chelyabinsk individuals show interesting variations in color that have nothing to do with rusting. It’s believed that varying amounts of oxygen available to the speeding rocks during the meteorite break up created the brownish-red coloration on some fusion crusts. Credit: Bob KingI saved the weirdest for last – a smaller Chelyabinsk meteorite appears to have followed closely enough behind the larger for their still-molten fusion crusts to have welded them together. Just my speculation. Credit: Bob King
In 1908 a blazing white line cut across the sky before exploding a few miles above the ground with a force one thousand times stronger than the nuclear blast that leveled Hiroshima, Japan.
The resulting shock wave felled trees across more than 800 square miles in the remote forests of Tunguska, Siberia.
For over 100 years, the exact origins of the Tunguska event have remained a mystery. Without any fragments or impact craters to study, astronomers have been left in the dark. That’s not to say that all kinds of extraordinary causes haven’t been invoked to explain the event. Various people have thought of everything from Earth colliding with a small black hole to the crash of a UFO.
Russian researchers claim they may finally have evidence that will dislodge all conspiracy theories, but that “may” is huge. A team of four believes they have recovered fragments of the object — the so-called Tunguska meteorite — and even think they are Martian in origin. The research, however, is being called into question.
In a detective-like manner, the team surveyed 100 years’ worth of research. The researchers read eyewitness reports and analyzed aerial photos of the location. They performed a systematic survey of the central region in the felled forest and analyzed exotic rocks and penetration funnels.
A schematic of the central region in the felled forest due to the Tunguska event. Image Credit: Anfinogenov et al.
Previously, numerous expeditions failed to recover any fragments that could be attributed conclusively to the long-sought Tunguska meteorite. But then Andrei Zlobin, of the Russian Academy of Sciences’ Vernadsky State Geological Museum, discovered three stones with possible traces of melting. He published the results in April 2013.
Zlobin’s discovery paper was received with skepticism and Universe Today covered the news immediately. A curious question arose quickly: why did it take so long for Zlobin to analyze his samples? The expedition took place in 1988, but it took 20 years before the three Tunguska candidates were nominated and another five years before Zlobin finished the paper.
By Zlobin’s admission, his discovery paper was only a preliminary study. He claimed he didn’t carry out a detailed chemical analysis of the rocks, which is necessary in order to reveal their true nature. Most field experts quickly dismissed the paper, feeling there was more work to be done before Zlobin could truly know if these rocks were fragments from the Tunguska meteor.
Today, new research is moving forward with an analysis of the rocks originally discovered by Zlobin. But an interesting new addition to the collection is a rock called “John’s Stone” — a large boulder discovered in July, 1972. While it’s mostly a dark gray now it was much lighter at the time of its discovery. “John’s Stone has an almond-like shape with one broken side,” lead author Dr. Yana Anfinogenov told Universe Today.
Now the skeptical reader might be asking the same question as before: why is there such a large time-lapse between the discovery of John’s Stone and the analysis presented here? (It’s interesting to note that while this elusive rock has been reviewed in the literature for over 40 years, this is the first time it has appeared in an English paper). Anfinogenov claimed that new data (especially concerning Martian geology) allowed for a much better analysis today than it did in recent years.
Photos (1972) of John’s Stone and related findings. Image Credit: Anfinovenov et al.
“The ground near John’s Stone presents undeniable impact signs suggesting that the boulder hit the ground with a catastrophic speed,” Anfinogenov told Universe Today. It left a deep trace in the permafrost which allowed researchers to note its trajectory and landing velocity coincides with that of the incoming Tunguska meteorite.
John’s Stone also contains shear-fractured splinter fragments with glossy coatings, indicating the strong effect of heat generated when it entered our atmosphere. The research team attempted to reproduce those glossy coatings found on the splinters by heating another fragment of John’s Stone to 500 degrees Celsius. The experiment was not successful as the fragment disintegrated in high heat.
“The authors do not present a strong case that the boulder known as John’s Stone was involved in the Tunguska event, or that it originated from Mars,” said Dr. Phil Bland, a meteorite expert at Curtin University in Perth, Australia.
They claim the mineral structure and chemical composition of the rocks — a quartz-sandstone with grain sizes of 0.5 to 1.5 cm and rich in silica — match rocks found on Mars. But their paper lacks any microanalysis of the samples, or isotopic study.
While there is a strong case that an impact on Mars could easily eject rock fragments that would then hit the Earth, something doesn’t match up. “The physics of ejecting material from Mars into interplanetary space argues for fragments with diameters of one to two meters, not the 20 to 30 meter range that would be required for Tunguska,” Bland told Universe Today.
It seems as though planetary geologists will require a much stronger case than this to be truly convinced John’s Stone is the Tunguska meteorite, let alone from Mars.
The paper is currently under peer-review but is available for download here.
What’s the oldest thing you’ve ever held in your hand? A piece of petrified wood? A fossilized trilobite? A chunk of glacier-carved granite? Those are some pretty old things, sure, but there are even older objects to be found across the world… that came from out of this world. And thanks to “Meteorite Men” co-host, author, and educator Geoff Notkin and his company Aerolite Meteorites, you can own a truly ancient piece of the Solar System that can date back over 4.5 billion years.
Founded in 2005, Aerolite (which is an archaic term for meteorite) offers many different varieties of meteorites for sale, from gorgeous specimens worthy of a world-class museum to smaller fragments that you could proudly — and economically — display on your desk. Recently I had the opportunity to talk in depth with Geoff about Aerolite and his life’s work as a meteorite collector and dealer. Here are some of the fascinating things he had to say…
So Geoff, what initially got you interested in meteorites and finding them for yourself?
“It’s been a lifelong passion for me, but I’m lucky in that I can really put my finger on a specific event when I was a kid and that was my mother taking me to the Geological Museum in London when I was six or seven… I was already a rock hound, I loved collecting fossils, and my dad was a very keen amateur astronomer. And so I had this love of astronomy and this fascination with other worlds for as long as I can remember. I’m a very tactile person; I’m very hands-on. I like to know how things work… I want to know all the bits and pieces. I was frustrated a bit, because I wanted to know more about astronomy. I could see all these planets and places through the ‘scope, but I couldn’t touch them. But I could touch rocks and fossils.
“So I’m six or seven years old, and I’m on the second floor of the Museum in the Hall of Rocks and Minerals. And at the back was this small display area that’s very dark. And you walked through an arch, it’s almost like walking into a cave. And it was very low light back there, and that was the meteorite collection.
“There were a couple of large meteorites on stands, and in those days — it was the late 60s — security wasn’t the issue that it is today. So you could touch the big specimens, and so I put my hands on these giant meteorites and I was absolutely enthralled. And I had this sort of epiphany: meteorites were the locus between my two interests, astronomy and rock-hounding. Because they’re rocks… they’re rock samples from outer space. I promised myself as a kid that one day I would have an actual meteorite.
“By finding or owning meteorites, you are forging a solid and tangible connection with astronomy.”
“Of course at the time there was no meteorite business, no meteorite magazines, there was no network of collectors like there is today. Back in the late 60s when I gave myself this challenge it was like saying I was going to start my own space program! But not only did it come true, it’s become my career.”
What makes Aerolite such a great place to buy meteorites?
“I think the caring for the subject matter really shows on the website. We have the best photography in the entire meteorite industry. I think we have the largest selection… we certainly spend a great deal of time discussing the history and importance of pieces… every single meteorite on our website has a detailed description and in most cases multiple photographs. My view is if you’re going to do something, you should really do it to the best of your ability. We don’t cut any corners, we don’t sell anything unless we’re one hundred percent sure of what it is and where it came from.
“I want buyers and visitors to look at the website and share my sense of wonder about meteorites. I think meteorites are the most wonderful things in existence, they’re actual visitors from outer space — they’re inanimate aliens that have landed on our planet.”
“We do this because we want to share our passion. We stand by every piece that we sell.”
How can people be sure they are getting actual meteorites (and not just funny-looking rocks?)
“This is something that’s more important to pay attention to now than ever. Are there fakes, are there shady people? Yes and yes. If you go on eBay at any given time you will find numerous pieces that are being offered for sale that are either not meteorites at all or are one thing being passed off as another thing. Sometimes this is malicious, sometimes people just don’t know any better. So the best way to buy a meteorite and know that it’s real is to buy from a respected dealer who has a solid history in the field.
“I’m by no means the only person who does this. There are a number of very well-established dealers around the world, and a good place to start is the International Meteorite Collectors Association(of which Geoff is a member) which is an international group with hundreds of members — collectors and dealers… it’s sort of a watchdog group that tries to maintain high standards of integrity in the field.
“My company has a very strict policy of never offering anything that’s questionable.”
“I see fakes all the time,” Geoff added. “On eBay, on websites, in newspaper ads… you do have to be careful. My company has a very strict policy of never offering anything that’s questionable. And we do get offered questionable things. There are some countries that have strict policies about exporting meteorites — Australia and Canada being two of them — and we work very closely with academia in both countries, and we have legally exported meteorites from those countries. Not only do we abide by international regulations, we actively support them.”
So you not only offer meteorites for sale to the general public, but you also donate to schools and museums.
“We work very closely with most of the world’s major meteorite institutions. I have provided specimens to the American Museum of Natural History in New York, the British Museum of Natural History in London, the Vienna Museum of Natural History, the Center for Meteorite Studies… we work with almost everyone. When we find something that is new or different or exciting, we always donate a piece or pieces to our colleagues in academia. It’s just the right thing, it’s the right thing to do if you discover something important to make it available to science.
“Most universities and museums don’t have acquisitions budgets and can’t afford to buy things that they might like to have. In return they classify the meteorites that we found, and they go into the permanent literature and become more valuable as a result. A meteorite with a history and a name and classification is worth more than a random meteorite that somebody just found in a desert. So everybody benefits, it’s a really good match.”
In other words, you really are making a contribution to science as opposed to just “looting.”
“Exactly. And I have, a very few times, gotten emails from disgruntled viewers who didn’t understand what we were doing, saying ‘what makes you think it’s okay to come to Australia and take our meteorites,’ for example. So I wrote a very courteous email back saying that we were in Australia with the express permission and cooperation of the Australian park services and one of the senior park rangers was there with us. And not only did we follow the proper procedure in having those specimens exported from Australia, I donated rare meteorites to collections just as a ‘thank you’ for working with us. It wasn’t a trade, it was a thank you. So everywhere we go, whatever we do, we try and leave a good impression.”
Geoff added, “I do this out of love… this isn’t the best way to make a living! Being a meteorite hunter is probably not the best capital return on your time but it’s a very exciting and rewarding life in every other way.”
And thus, by buying meteorites from Aerolite, customers aren’t just helping pay for your expeditions and your work but also supporting research and education too.
“People who purchase from us are really participating in the growth of this science. Also, something very near and dear to my heart is science education for kids. You know that I am the host of an educational series called STEM Journals, which is a very — I think — amusing, entertaining, funny, fast-paced look at science, technology, engineering, and math topics. But you can’t make a living doing television shows like that. This is a labor of love… we do it because we think it’s important. If I didn’t have a commercial meteorite company to help underwrite the costs of educational programming and educational books, we just couldn’t do it. It’s as simple as that.
“So we always try to give back. That’s why I speak at schools and universities and give away meteorites to deserving kids at gem shows… because it was done to me when I was seven years old. The look of wonder you see on a kid’s face when you connect with them and they start to grasp the wonder of science… that’s something they’ll never forget.”
That’s great. And it sounds like you haven’t forgotten it yet either!
“I must say after all these years, I’ve been doing this close to full time for nearly twenty years and you never lose the amazement and the wonder of when a meteorite’s found or uncovered. I never go ‘oh, jeez, it’s just another billion-year-old space rock that fell to Earth!’ So it is a privilege to be in a work field where almost daily something wondrous happens.”
As we here at Universe Today know, when it concerns space that’s a common occurrence!
“Exactly!”
One last thing Geoff… do you think we’ll ever run out of meteorites?
“The meteorite collecting field has grown tremendously in the past ten years, and Meteorite Men is part of that. There is a finite supply of meteorites. Of course there are more landing all the time, but not enough to replenish the demand. Periodically there is a new very large discovery made, such as the Gebil Kamil iron in Egypt a couple of years ago. But what is happening is a significant increase in price and a decrease in selection, so some of the real staples we used to see… you can’t get them anymore.
“Still, people who want a meteorite collection, now is a great time for them to be buying because there are more meteorites available than in the past — but it’s not going to stay that way for very long. It’s like any other collectible that has a finite supply.”
Makes sense… I’ll take that as ‘inside advice’ to place an order soon!
______________
My thanks to Geoff for the chance to talk with him a little bit about his fascinating past, his passion, and his company. And as an added bonus to Universe Today readers, Geoff is extending a special 15% off on orders from Aerolite Meteorites — simply mention the code UNIVERSETODAY when you place an order!* (Trust me — once you browse through the site you’ll find something you want.) Also, if you’re in the Tucson area, Geoff Notkin and Aerolite Meteorites will have a table at the Tucson Gem and Mineral Show starting Jan. 31.
One of several meteorite-hunting books by Geoff, featuring an introduction by Neil Gaiman.
Be sure to check out Geoff’s television show STEM Journals on COX7 — the full first two seasons can be found online here and here, and shooting for the third season will be underway soon.
Want to know how to find “inanimate aliens” for yourself? You can find Geoff’s books on meteorite hunting here, as well as some of the right equipment for the job.
The 20-foot (6-meter) hole punched through the ice on Chebarkul Lake by a large fragment of the Chelyabinsk meteorite. Credit: AP
Security camera video showing the impact of the largest piece of the Chelyabinsk meteorite striking Lake Chebarkul during the Feb. 15, 2013 Russian fireball. Credit: Nikolaj Mel’nikov.
When I first watched this video of the half-ton Chelyabinsk meteorite crashing into Lake Chebarkul last Feb. 15 I didn’t see anything. But once you pay close attention, what you’ll see is nothing short of amazing. You’ll recall that a 20-foot (6 meter) hole appeared in the ice immediately after the fall. While no one witnessed the impact, a security camera caught the critical moment from the other side of the lake.
The video recently appeared in an online presentation by Peter Jenniskens, noted meteorite expert and senior research scientist at the SETI Institute. It was released as part of a paper and Powerpoint on the Chelyabinsk airburst. You can listen to Jenniskens’ presentation HERE.
Frame grab from the video showing the breakdown of the impact and resulting ice and snow cloud.
When you watch the video, focus your attention just to the left of what looks like an ice fishing shack at top center and use the handy frame grab above. In the slowed-down portion of the footage you’ll see a cloud of ice and snow blow up and quickly drift to the right of the shack seconds after impact. While blurry and small, it’s amazing good fortune we have a document of this fall.
Video of the recovery of the largest piece of the Chelyabinsk meteorite
Divers ultimately fished the 1/2 ton Chelyabinsk meteorite – the largest found so far – from the lake on Oct. 16. It measured 5 feet long (1.5 meter) and broke into three pieces as scientists hoisted it into a scale to weigh it.
As a return favor, the little piece of heaven broke the scale.
